The present invention relates to apparatus for effecting scarification of surfaces such as concrete by means of water jets.
As is known, the possibility of cutting or piercing stone materials, and in particular, concrete, with water jets at high pressure or, rather, at high velocity has been studied in an experimental way.
Only recently, however, has the problem of the scarification of concrete with jets of water been considered, for the purpose of the removal of a layer of constant (or variable) thickness from a flat or curved surface. It is likewise known that much research has been conducted in an attempt to try and resolve this problem but with little success, attributable largely to the instability of the water jets and an incorrect distance between the jets and the surface to be scarified, as well as to the lack of movement of the nozzles themselves. It is known that the instability of the jets manifests itself as the formation of surface waves which lead to the production of drops or droplets the energy of which is rapidly dissipated into the air due to the high surface-to-volume ratio.
This phenomen is encouraged by various parameters such as: the high eflux velocity; the small diameter of the jet; the sharp variations in cross-section; the presence of gas in solution; etc. Moreover, the possible presence of sand particles in the water used leads, especially in the high pressure compression units, to a rapid wear of the units themselves.